Solid golf balls are usually two or more piece constructions. Two-piece golf balls include a single-piece core and a cover. A subassembly comprises a core and any layers that the cover surrounds. Three-piece golf balls include a core, an intermediate layer, and a cover. In such balls, the core and intermediate layer may form the golf ball subassembly that the cover surrounds.
For premium golf balls, the cover material typically comprises thermosetting polyurethane. One method of making polyurethane-covered golf balls includes disposing the golf ball subassembly into a cover mold and casting the cover thereon.
The use of urethane polymers has been proposed for golf ball cover compositions. One patent teaches of the initial forming of two urethane shell blanks to make cover halves (U.S. Pat. No. 3,989,568). Another patent suggests forming a smooth cover and thereafter impressing dimples in the smooth cover (U.S. Pat. No. 5,006,297). Still another patent describes a sequence of filling first half of a mold with urethane, inserting a ball center therein and later adding more urethane to a second half and uniting the second with the first half (U.S. Pat. No. 3,147,324). The basic principle of the '324 patent is still seen today, albeit many modifications having been made over the years to solve inherent process problems.
The present invention seeks to improve present day methods of making urethane covered golf balls by introducing new automation processes that increase product volume without increasing working area or manpower.